Vibration of handheld electric power tools is measured in accordance to EN 60745 series
EN 60745 which measures vibration in three directions (otherwise known as a tri-axial or vector sum measurement). This has been developed to replace the older version of EN 60745 standard and bring the manufacturers vibration measurement procedures in line with the HAV Directive.
m/s² = √ X² + Y² + Z²
In reality there are far too many variables which can affect the outcome of the measurement. The DEWALT view is that job site measurement is too UNRELIABLE. DEWALT recommends that manufacturers values are used for calculating HAV exposure levels providing they are specifically identified as ‘Tri-Axial’ or ‘Estimated Tri-Axial’ according to HSE guidelines and EN 60745-1:2006 and reflect vibration values in the so called upper quartile.
VIBRATIONS EXPOSURE LIMITS
Exposure limits are calculated as a combination of the vibration level (magnitude) of the tool and the Daily Exposure Time (Trigger Time). E.g. A product with 5m/s² vibration can be used up to 2 hours/day to reach the EAV and up to 8 hours/day to reach the ELV.
Regular and frequent exposure to high levels of vibration can lead to permanent injury.
This is most likely when contact with a vibrating tool or process is a regular part of a person’s job. Occasional exposure is unlikely to cause injury, although it should be avoided by people with medical conditions such as Raynaud’s Disease.
Equipment manufacturers are generally trying to improve the vibration performance of their products, so new tools and machines are likely to emit lower vibration than older equipment. You will gain the maximum benefit from these improvements if you introduce a policy of buying the most suitable equipment when you replace tools or machines. DEWALT prides itself on innovation, and there for its range of hammers and other high risk products are some of the most up to date products on the market. Focusing on combating vibration at source (active vibration Control), DEWALT’s range of products demonstrate some of the loest vibration figures on the market.
For most types of equipment, manufacturers are required by law to:
Design and construct equipment which will cause the minimum risk of vibration injury;
provide you with warning of any residual risks from vibration;
provide you with information on vibration levels;
provide you with instructions on how to use the equipment to avoid risks from vibration.
The documentation supplied by the equipment manufacturer should warn you of risks from vibration. You can also check yourself to see if hand-held power tools, hand-guided and hand-fed machines are regularly used, and if so, whether anyone is, in particular using vibrating tools each day. If so, your employees are probably at risk. Even where employees are using vibrating tools or machines for less than these times, there may still be a risk and you should regularly (at least every six months) ask them if they are getting any symptoms of HAVS. Some simple questions you could ask are:
Have your fingers gone white on exposure to cold?
Have you had any tingling or numbness in your fingers after using vibrating equipment?
Are you experiencing any problems with muscles or joints in your hands or arms?
Do you have any difficulty picking up small objects such as screws or nails?
If the answer to any of these questions is ‘yes’, assume that there is a risk from HAV to your employees. You should refer the employee to a doctor and take action to reduce exposure.
There is more detailed guidance on what you can do to assess the risk in HSE’s publication Hand-arm vibration